The application relates to a method of repairing a blade airfoil, wherein additional material secures to a cap secured to the blade.
Gas turbine engines are known and typically include multiple sections, such as a fan, a compression section, a combustor section, a turbine section, and an exhaust nozzle. Blades are mounted within the compressor and turbine sections. The blades have airfoils extending from a platform toward a blade tip.
Rotating blades compress air in the compression section. The compressed air mixes with fuel and is combusted in the combustor section. Products of combustion expand to rotatably drive blades in the turbine section. As the blades are often exposed to extreme temperatures, some blades, especially the turbine blades, include internal channels for routing cooling air.
Some blades rub against other portions of the engine when rotating. The engine dimensions are controlled to prevent too much rubbing, which can fracture the blade or bind the engine. Rubbing wears and stresses the blades, particularly near the blade tip. Replacing an entire worn blade is often expensive due to material and machining costs.
To prevent replacing the entire blade, the worn area is often removed and replaced with a build-up of weld material that is then machined to an appropriate airfoil shape. But other areas of the blade, such as braze material from the OEM production process, can contaminate the build-up, and as known, contaminants weaken welds.
Therefore, what is needed is a method of repairing an airfoil that lessens contaminants in the repairing weld, especially repairing welds near the tip of the airfoil.